SOLUTION: How do you prove that {{{cos(5x) = 5 cos(x) - 20 cos^3(x) + 16 cos^5(x)}}} using sum and difference identities? Thank you :D
*EDIT: I'm so sorry, cos^5 x should be cos 5x
Algebra.Com
Question 604252: How do you prove that using sum and difference identities? Thank you :D
*EDIT: I'm so sorry, cos^5 x should be cos 5x
Found 2 solutions by jsmallt9, jjvseg:
Answer by jsmallt9(3758) (Show Source): You can put this solution on YOUR website!
This cannot be correct because ...- What you posted was:
This is not an identity. This equation is only true for certain values of x, not all values of x.; and - All the arguments are x. There is no need to use sum and/or difference identities to manipulate the arguments.
If you re-post the question, then I wonder if the double angle and half angle identities would be considered "sum and difference identities"? I ask because I suspect that they might be very helpful.
Answer by jjvseg(1) (Show Source): You can put this solution on YOUR website!
RELATED QUESTIONS
Prove using trig identities
cos3x=cos^3(x)-3sin^2(x)cos(x)
Thank... (answered by MathLover1)
How do you find the cos of 55 degrees using the sum and difference identity?
cos... (answered by Edwin McCravy)
How do I prove that (cos^3(x)+ sin^2(x)cos(x))/(cos(x))=tan(x) is an... (answered by ikleyn)
Prove this with trig identities
((sin(x))/(1+cos(x)))+((1+cos(x))/(sin(x))) = 2csc(x)
(answered by MathLover1)
How to prove identities?
like 1 + cos x / 1+ sec x =cos x.
The equals mean... (answered by ewatrrr)
"compute the exact values of sin 2x, cos 2x, tan 2x without a calculator. Cos x= (-4/5),... (answered by Edwin McCravy)
How do I simplify {{{cos(2x-pi/2)}}} using sum and difference... (answered by ikleyn)
Please prove this using Trigonometric Identities:
sin⁴x - cos⁴x + cos²x =... (answered by lwsshak3)
how do you solve 3 cos(x)+4=5 cos(x)+5 on the interval... (answered by lwsshak3)